1. Field of the Invention
The present invention relates to impact-modified polycarbonate moulding compositions comprising mixtures of graft polymers prepared in the emulsion polymerization process and in the bulk, solution or suspension polymerization process having a defined particle size distribution, which on the one hand are suitable for the production, over a wide processing window (i.e. also at high processing temperatures), of non-lacquered components having a high gloss surface and on the other hand are capable of precise imaging of fine-grained or surface-etched mould surfaces. By this means, components having both high gloss and deep matt component sections can be realized in a mould with different surface textures in a single injection moulding step without further after-treatment of the surface. The moulding compositions have a high heat distortion temperature and ductility at low temperatures and an excellent resistance to stress cracking under the influence of chemicals, which is particularly important for non-lacquered components.
The present invention also relates to the use of the polycarbonate moulding compositions according to the invention for the production of shaped bodies or mouldings which can be produced in a single production step in the injection moulding process without further surface after-treatment steps and which have both high gloss and deep matt component sections.
The present invention moreover also relates to the shaped bodies or mouldings from the compositions according to the invention which can be produced in a single production step in the injection moulding process without further surface after treatment steps and which have both high gloss and deep mat component sections.
2. Description of Related Art
Impact-modified polycarbonate compositions comprising mixtures of graft polymers of defined particle size are known from the literature.
EP 1 141 123 B1 discloses highly impact-modified thermoplastic moulding compositions comprising a graft polymer prepared in the emulsion polymerization process having a trimodal rubber particle size distribution, a graft polymer prepared in the solution, bulk or suspension polymerization process and a rubber-free copolymer of styrene and acrylonitrile, which optionally can comprise a further resin, including also aromatic polycarbonate or polyester carbonate.
EP 488 930 B1 discloses ABS moulding compositions of high toughness, sufficiently high heat distortion temperature, excellent thermoplastic processability and a low surface gloss which can be adjusted in a controlled manner, comprising a mixture of three thermoplastic co- or terpolymers of different molecular weight, a graft polymer having an average particle diameter (D50) of from 50 to 500 nm, which has preferably been prepared by emulsion polymerization, a further graft polymer having an average particle diameter (D50) of from 1,000 to 5,000 nm, which has preferably been prepared by solution or bulk polymerization, and aromatic polycarbonate.
WO 99/65991 A1 describes compositions which are suitable for galvanization and comprise polycarbonate, styrene copolymer, a first graft polymer, preferably prepared in emulsion polymerization, based on a rubber base having an average particle diameter (D50) of from 50 to 500 nm and a second graft polymer, preferably prepared in bulk, solution or suspension polymerization, based on a rubber base having an average particle diameter (D50) of from 600 to 20,000 nm.
U.S. Pat. No. 4,677,162 discloses moulding compositions of low temperature toughness and low gloss comprising polycarbonate, bulk ABS having an average particle size of greater than 750 nm and an impact-modifying graft polymer having an average rubber particle size of below 750 nm.
DE 40 14 419 A1 discloses thermoplastic moulding compositions having good flow properties, a good low temperature toughness and high heat stability comprising polycarbonate, a first graft polymer prepared in the bulk, solution or suspension process having an average particle diameter of the grafted rubber particles of from 500 to 5,000 nm and a second graft polymer prepared in the emulsion polymerization process having a graft base having an average particle diameter (D50) of from 50 to 2,000 nm.
EP 312 929 A2 describes thermoplastic moulding compositions having a good toughness, flowability, high gloss and good resistance to weathering comprising polycarbonate and a mixture of two graft polymers, wherein the first graft polymer, prepared by emulsion polymerization, is based on an elastomeric graft base having an average particle diameter (D50) of from 50 to 500 nm and the second graft polymer, prepared by bulk, solution or suspension polymerization, has an average particle diameter of from 800 to 5,000 nm.
EP 1 960 467 A1 discloses compositions of excellent low temperature ductility and improved processing properties comprising polycarbonate, two graft polymers, optionally a (co)polymer, characterized in that the weight-average molecular weight of the free (co)polymer in the first graft polymer differs from the weight-average molecular weight of the mixture of the free (co)polymer in the second graft polymer and the (co)polymer optionally added separately by at least 32,000 g/mol. In a preferred embodiment one of the two graft polymers and in a particularly preferred embodiment both graft polymers are a bulk, solution or suspension polymer.